Scotland's Russell Knox continued to make the most of his late entry into the final World Golf Championship event of the season as a frustrated Rory McIlroy slipped down the leaderboard in Shanghai.
McIlroy is now ten shots off the lead and let his temper get the better of him, hitting his bag with a club and rushing shots.
Knox was initially seventh reserve for the €7.8 million HSBC Champions at Sheshan International.
He squeezed in when other players pulled out and now finds himself competing for a first European Tour title and the winner’s prize of €1.25 million.
The 30-year-old from Inverness carded an opening 67 and added a flawless 65 in tougher, blustery conditions on Friday to lie two shots behind American Kevin Kisner.
Kisner added a 66 to his opening 64 for a combined halfway total of 14 under and has not dropped a shot in 36 holes.
Knox found out he would be making his WGC debut while playing in the CIMB Classic in Malaysia last Friday and praised his wife Andrea for making the necessary arrangements - and also stepping in as a temporary caddie.
"My wife was a superstar and she filled out all the forms for us," said Knox, who made his Open debut at St Andrews in July after McIlroy was forced to withdraw due to the ankle injury suffered playing football with friends.
"While we were playing on Friday she took all the stuff to the Chinese embassy in Kuala Lumpur and had it processed. Then we had to wait around until Monday at 2pm to get them back and they gave us our passports.
"We flew here on Tuesday morning but my caddie didn't have proof of accommodation so he was a day behind us. So when we got here my wife caddied for me.
“We got a stand bag from the pro here and chucked the clubs in and played the quickest practice round ever and she complained heavily for the last nine holes!"
McIlroy, who recovered from a bout of food poisoning to card a 68 on Thursday came within inches of a hole-in-one on the 12th.
But he bogeyed the 13th after missing the green and was furious with another pulled iron shot on the short 16th.
He slammed his club into the bag and then barely bothering to line up a par putt from four feet, which he duly missed.
Things looked set to get even worse on the last when McIlroy found water with his approach and had to let two more balls roll into the hazard as he took a penalty drop on a steep slope short of the green.
However, the four-time major winner pitched to four feet to save par and signed for a level-par 72 which left him four under overall.
Shane Lowry carded a three over second round to sit on five over, leaving just six golfers behind him on the leaderboard.
"I didn't play very well today. I was just a bit flat out there," said a dejected McIlroy.
"I've left myself a lot to do over the weekend but hopefully I can shoot a couple of good scores and get myself back up the leaderboard.
"I wouldn't say I'm 100 per cent. I struggled to hit balls today on the range, got a few cramps in the stomach. But I took a couple of tablets and it sort of went away as I went through the round."
